Light bulb



' Aug. 24, 1943. R BOARD'MAN 2,327,396

LIGHT BULB Filed March 15, 1941 3 w mvto c RAYMOND BOARDMAN Patented Au. 24, 1943 PATENT OFFICE LIGHT BULB Raymond BoardmamI-Iartford, 001111., assignor to The Hart Manufacturing Company, Hartford, Conn, a corporation of Connecticut Application March 15, 1941, ScrialNo. 383,597

ciaims. (o1. 1 7c' 1'22)' The present invention relates to electric light bulbs and more particularly to small bulbs of the type which are filled with an inert gas, such as neon and which are readily mountable and replaceable on an instrument panel for use as pilot or indicating lights. Because of the relative small size of sueha bulb, resistance must be electrically connected in series with it, in order to reduce to a sufficiently low potential intensity the electric current supplied ther o. Heretoi'ore, a separate resistance element been electrically wired-to the. ligh bulb in order to provide the necessary high resistance.

It is an object of the present invention to eliminate the necessity for a separate resistance ele ment by providing a neon bulb having resistance portions formed integral therewith.

It is a further object to provide a bulb wherein the aforesaid resistance portions are formed of a self-adhering carbonaceous material which is applied in strips :to the external surface of the bulb and wherein the resistances serve as contacts'with which to electrically connect the bulb to terminals connected to a source of current supply. In this connection, the terminals adapted to set up a potential between the formay be in the form of a pair of resilient arms which electrically contact the resistances and at the same time mount the bulb in such a manner as to make it readily replaceable.

A still further object is to provide a bulb of the typeindicated that can be manufactured, assembled and replaced'easily and inexpensively.

Cther objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and :le scope of the application of which will dicated in the appended claims.

In the accompanying drawing:

Figure 1 is a side profile View of a neon light bulb constructed in accordance with the present invention and illustrated properly installed in a suitable mounting;

Fig. 2 is a rear profile view of thebulb and mounting illustrated in Figure 1; and

Fig. 3 is an enlarged cross-sectional View taken substantially through line of Figure l.

The drawing illustrates generally neon light bulb B including the usual blown glass casin H3 having a chamber 12 in which the customary current conducting electrodes 54 are located and from which the atmospheric air has been exhausted and replaced by an inert gas, such as ward tips'22 so as to illuminate the neon orother inert gas contained therein when current is supplied to the electrode tips or leads 24 which extend a slight distance outwardly of the bulb base 20. r

'A pair of; resistances 26 are provided on the bulb for reducing the potential and intensity'of the current supplied to the electrodes 24. According to the present invention the resistances are'formed by coating water glass, or similar self-adhering material, containing fine carbon particles in strips along diametrically opposed sides of the glass bulb. Each resistance strip 26 contacts an exposed lead 24 and establishes electrical contact therewith. The water glass for other self-adhering material may be easily ap plied to the surface of the bulb substantially as shown in the drawing and by varying the carbon content the resistance of the strips can be predetermined so as to limit the current leading from the source of supply to the proper rating for the bulb.

The strips 26 not only serve as resistance elements but also serve as contacts for establishing electrical connections between the electrodes 14 and suitable resilient arms 28, the arms being further adapted to support the bulb in the positicn desired. In the present instance the arms 28 are suitably curved as at 29 so as to properly mate with the bulb curvature and contact the be instrips. The arms 23 may be fastened to an insulated board 3!! by suitable screws 32, the screws also serving as terminals to plied as by the wires 34.

The present invention thus provides an easily mountable and electrically connectible small neon bulb having integral resistance elements which serve as contacts for engagin and electrically connecting the bulb to the current supply terminals.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

which current is sup- It is also to be understood that the language used in the following claims is intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

I claim as my invention:

1. The combination with xa 'pair of spaced spring contact arms, of alight bulb adapted to be removably supported between said arms and supplied with electric current by said arms, said bulb comprising a hollow glass body closed at both ends and filled with an inert gas, a pair of electrodes embedded in one of said closed endsof the body and extending into said hollow-body in spaced relation to each other and to the walls of the body, the outer ends of said electrodes extending through the end of the body to forrna pair of exposed leads, and a resistor strip contacting each of said exposed leads all extending along the exterior surface of the body for a substantial distanca' said resistor stripsbeing adapted to engage the spring contact arms for conducting electric'current to the electrodes while setting up a resistance to the passage of the electric current.

2, The combination with a pair of spaced spring contact arms, of a light bulb adapted to be removably supported between said arms'an'd "supplied with electric current by said arms, said bulb comprisin -a hollow glass body closed at both ends and filled with an inert gas, a pair of electrodes embedded in one of said closed ends of the body and extending into said'hollow body in spaced relation to each other and to the walls of the body, the'outer ends of said electrodes extending throughithe end of the body to form a pair of exposed leads, and a resistor strip contacting'each of said exposed leads all extending along the exterior surface of the body fora substantial dis tance, said resistor strips being adapted to engage the spring contact arms for conducting electric current to the electrodes while setting up a resistance to the passage of the electric current and said resistor strips being coated onto the body and composed of an adhesive impregnated with a material having a, high electrical resistance.

3. A neon light bulb comprising a generally cylindrical hollow sealed glass body filled with neon gas, one end of said glass bod having a thickened wall, a pair of electrodes embedded in said thickened end wall and extending into the hollow body in spaced relation to each other and to the side walls of the body, the outer ends of the electrodes projecting through and beyond the thickened end wall of the body to form a pair of exposed leads,. and a resistor strip contacting each of said exposed leads and extending along the exterior surface of the body for a substantial distance, said resistor strips being adapted to conduct electric current to the electrodes While 1 settingup a resistance to the passage of the electric current.

-i. A neon light bulb comprising a generally cylindrical hollow sealed glass body filled with neon gas, one end of said glass body having a thickened wall, a pair of electrodes embedded in said thickened end wall and extending into the hollow body in spaced relation to each other "l to the side walls of the body, the outer s of the electrodes projecting through and beyond the thickened end wall of the bodyto form a pair of exposed leads, and a resistor strip contacting each of said exposed leads and extending along the exterior surface of the body for a substantial distance, said resistor strips being adapted to conduct electric current to the electrodes while setting up a resistance to the passage of the electric current, and said resistor strips being coated onto the glass body and composed of an adhesive impregnated with a material having high 'electrical resistance.

RAYIWOND BOARDNIAN., 

